Which number will replace the question mark (?) in the following series?
64, 65, 69, 78, 94, ?
- A122
- B121
- C119
- D120
Solution & Step-by-step Explanation
Let's find the difference between consecutive numbers in the series:
65−64=1=1
2
69−65=4=2
2
78−69=9=3
2
94−78=16=4
2
The differences are consecutive perfect squares (1
2
,2
2
,3
2
,4
2
).
The next difference must be 5
2
=25.
Missing number=94+25=119
65−64=1=1
2
69−65=4=2
2
78−69=9=3
2
94−78=16=4
2
The differences are consecutive perfect squares (1
2
,2
2
,3
2
,4
2
).
The next difference must be 5
2
=25.
Missing number=94+25=119